The camera for the Campaign intro just sort-of clips through the ground when starting this campaign, plus I also noticed that intros for Dead Center and some other custom campaigns were also broken while these addons were enabled. I looked it up and I believe this campaign was responsible for the broken camera:

https://www.reddit.com/r/l4d2/comments/10lm4vi/this_happens_at_the_very_start_of_every_campaign/